Sound pressure distribution within natural and artificial human ear canals: Forward stimulation

Ravicz, Michael E.; Cheng, Jeffrey; Rosowski, John J.

doi:10.1121/1.4898420

Cited by 16 publications

(20 citation statements)

References 35 publications

(77 reference statements)

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“…These measurements and modeling results led us to suggest a modal motion theory of TM sound transmission, where acoustic energy is mainly coupled to the middle-ear ossicular chain through low-order modal motion components on the TM surface (Cheng et al, 2013). This theory is consistent with the relatively uniform sound pressure distribution observed over the entire TM surface at frequencies up to about 15 kHz (Stinson, 1985;Ravicz et al, 2014;Cheng et al, 2015), where the uniform sound pressure is the source of the low-order standing-wavelike modal motions of the TM. The contribution of highorder traveling-wave-like TM motion components to middle-ear function is still under debate (Puria and Allen, 1998;Parent and Allen, 2010;de La Rochefoucauld and Olson, 2010;Goll and Dalhoff, 2011;Cheng et al, 2013).…”

Section: Introductionsupporting

confidence: 65%

Tympanic membrane surface motions in forward and reverse middle ear transmissions

Cheng

Maftoon

Guignard

et al. 2019

The Journal of the Acoustical Society of America

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Characterization of Tympanic Membrane (TM) surface motions with forward and reverse stimulation is important to understanding how the TM transduces acoustical and mechanical energy in both directions. In this paper, stroboscopic opto-electronic holography is used to quantify motions of the entire TM surface induced by forward sound and reverse mechanical stimulation in human cadaveric ears from 0.25 to 18.4 kHz. The forward sound stimulus was coupled to an anatomically realistic artificial ear canal that allowed optical access to the entire TM surface, and the reverse mechanical stimulus was applied to the body of the incus by a piezo-electric stimulator. The results show clear differences in TM surface motions evoked by the two stimuli. In the forward case, TM motion is dominated by standing-wave-like modal motions that are consistent with a relatively uniform sound-pressure load over the entire TM surface. With reverse mechanical stimulation, the TM surface shows more traveling waves, consistent with a localized mechanical drive applied to the manubrium embedded in the TM. With both stimuli, the manubrium moves less than the rest of the TM, consistent with the TM acting like a compliant membrane rather than a stiff diaphragm, and also consistent with catenary behavior due to the TM's curved shape.

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Section: Introductionsupporting

confidence: 65%

Tympanic membrane surface motions in forward and reverse middle ear transmissions

Cheng

Maftoon

Guignard

et al. 2019

The Journal of the Acoustical Society of America

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“…A study (Ravicz et al, 2014) of the pressure field close to the TM referred to the difficulty of defining an input admittance at the TM due to the spatial extent of the TM, the inhomogeneity of the sound field across the TM, and the complex TM motions that are not well correlated to the sound field distribution. The ease of using a one-dimensional description of the sound field is contrasted with the fact that the sound field and the motions on the TM, which forms a part of the boundary of the ear canal, have complex spatial interactions.…”

Section: Methodsmentioning

confidence: 99%

Procedures for ambient-pressure and tympanometric tests of aural acoustic reflectance and admittance in human infants and adults

Keefe

Hunter

Feeney

et al. 2015

The Journal of the Acoustical Society of America

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Procedures are described to measure acoustic reflectance and admittance in human adult and infant ears at frequencies from 0.2 to 8 kHz. Transfer functions were measured at ambient pressure in the ear canal, and as down- or up-swept tympanograms. Acoustically estimated ear-canal area was used to calculate ear reflectance, which was parameterized by absorbance and group delay over all frequencies (and pressures), with substantial data reduction for tympanograms. Admittance measured at the probe tip in adults was transformed into an equivalent admittance at the eardrum using a transmission-line model for an ear canal with specified area and ear-canal length. Ear-canal length was estimated from group delay around the frequency above 2 kHz of minimum absorbance. Illustrative measurements in ears with normal function are described for an adult, and two infants at 1 month of age with normal hearing and a conductive hearing loss. The sensitivity of this equivalent eardrum admittance was calculated for varying estimates of area and length. Infant-ear patterns of absorbance peaks aligned in frequency with dips in group delay were explained by a model of resonant canal-wall mobility. Procedures will be applied in a large study of wideband clinical diagnosis and monitoring of middle-ear and cochlear function.

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“…Sound stimuli activate the entire TM nearly identically and simultaneously (Ravicz et al 2014), and motion of the umbo in response to acoustic transients (“clicks”) represents a summing of the contributions of the entire surface of the TM to umbo motion, where the contribution of different TM locations to the total umbo motion may vary with location and frequency. In contrast, mechanical transients (“pokes”) that directly stimulate only a discrete small region of the TM allow the assessment of how individual small regions contribute to the motion of the umbo.…”

Section: Introductionmentioning

confidence: 99%

Response of the human tympanic membrane to transient acoustic and mechanical stimuli: Preliminary results

et al. 2016

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The response of the tympanic membrane (TM) to transient environmental sounds and the contributions of different parts of the TM to middle-ear sound transmission were investigated by measuring the TM response to global transients (acoustic clicks) and to local transients (mechanical impulses) applied to the umbo and various locations on the TM. A lightly-fixed human temporal bone was prepared by removing the ear canal, inner ear, and stapes, leaving the incus, malleus, and TM intact. Motion of nearly the entire TM was measured by a digital holography system with a high speed camera at a rate of 42 000 frames per second, giving a temporal resolution of <24 μs for the duration of the TM response. The entire TM responded nearly instantaneously to acoustic transient stimuli, though the peak displacement and decay time constant varied with location. With local mechanical transients, the TM responded first locally at the site of stimulation, and the response spread approximately symmetrically and circumferentially around the umbo and manubrium. Acoustic and mechanical transients provide distinct and complementary stimuli for the study of TM response. Spatial variations in decay and rate of spread of response imply local variations in TM stiffness, mass, and damping.

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Sound pressure distribution within natural and artificial human ear canals: Forward stimulation

Cited by 16 publications

References 35 publications

Tympanic membrane surface motions in forward and reverse middle ear transmissions

Tympanic membrane surface motions in forward and reverse middle ear transmissions

Procedures for ambient-pressure and tympanometric tests of aural acoustic reflectance and admittance in human infants and adults

Response of the human tympanic membrane to transient acoustic and mechanical stimuli: Preliminary results

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